C18-ceramide production by CerS1 is inhibited in HNSCC through transcriptional repression via histone deacetylase 1 (HDAC1)-dependent inhibition of Sp1 at the promoter, and post-transcriptionally by miR574-5p that induces translation of a CerS1 isoform 2 splice variant common in HNSCC tumor tissues [65]. This evidence concerns the gene SP1 and head and neck squamous cell carcinoma.